Automatic switch



E. W. BOTTS oct. 4, 1932.

AUTOMATIC SWITCH Filed NOV. l5, 1929 ATTORNEY Patented Oct. 4, 1932UNITED STATES EDWARD W. IBOTTS, F CHICAGO, ILLINOIS AUTOMATIC SWITCHApplication led November 13, 1929. Serial No. 406,775.

My invention relates to improvements in automaticmake and break switchesfor automobile stop lights and the like and has for one object toprovide a super-sensitive make and break switch which may be enclosed ina light and portable housing and which may be placed in series withautomobile stop or signal lights and wherein the assembly may be mountedasvpart of the wiring system supported by the wires and without relationto any other part of the vehicle. Other objects `will appear from timeto time throughout the specication and claims.

v My invention is illustrated more or less diagrammatically in theaccompanying drawing, wherein- Figure 1 is an end view of the device;Figure 2 is a section along the line lill-lll of Figure l; Figure 3 is asection along the line Ill-lill of Figure 1 Figure 4 is a detail on anenlarged scale.

Like parts are indicated by like characters throughout the specificationand drawing.-

A is a housing. It is preferably cylindrical and preferably made of beror other suitable insulating material. It is closed at each end by plugsA1 A2 of fibrous material, preferably asbests or mineral wool. The

* purpose of these plugs is to furnish a support and limit'for theinward flow into the tube or housing of the insulating, sealing ends orclosures A3 A* which are poured in place and permanently close the unit.

B is a switch frame contained within the housing and insulated from theelectric parts as indicated. Mounted on the upper end of the frame B isa switch arm B1 made of two materials having different co-eflicients'ofexpension as for instance brass and iron, which materials also serve asa conductor. This arm is rigidly mounted on and is in electricalconnection with the frame B. In opposition to this arm is a similarswitch arm B2 which is supported on the frame B and insulated therefrom.Wound about this arm is a resistance coil B3 insulated of coursetherefrom. One terminal of .this coil is connected as at B4 to theanchored base of the arm B1, the other terminal is connected as at B5 tothe enlarged 50 base of the arm B2. Make and break points B6 are mountedin opposition to the free ends of the switch arms B1 B2.

A conductor C having an insulated jacket C1 embedded in the plug A4 isconnected to 55 the switch arm B2. A conductor C2 insulated at C3 andembedded in the plug A3 engages the arm B1. rlhese two conductors bytheir engagement with the ends of the arms B1 and B2 which are rigidlymounted on the frame B, eo h old the frame, the switch arms, and theresistance coil firmly in place in the housing, the ber plugs having nofunction so far as holding the parts together or in place are concerned,they being there only for the purpose ce as above indicated ofpreventing the liquid from which the plug is cast flowing too far intothe housing. C* is a cup extending outwardly Jrom the plug A3 andcontaining a resistance coil C5, one end of which is in electu triccircuit with the arm B1, the other end C8 leading out from the cup. Thewire C is preferably connected to the battery, generator, or othersuitable source of electric power. rlhe wire()6 is grounded. The wire 75C2 is connected through a main control switch to the light circuit.rl`his switch maybe the usual type of switch responsive to the movementof the foot pedal'of anautomobile to indica-te a stop or may be a signalswitch controlled by the hand of the operator or any other type ofswitch manually or automatically controlled to operate a lamp signal orother circuit.

The two switch arms are both of them bimetallic so that they will bothrespond equally to changes in the normal temperature of the apparatusand render it immune to change resulting from changes in location of thestructure or changes in the temperature to which the entire apparatus isexposed, thus making it possible to have a comparatively sensitiveswitch element. This is important if the device is, for instance,applied to an automobile in the FarNorth or in theTropics. The reactionof the two switch arms to such change being the same `willnot cause anychange in their operation.

When current flows through the coil B3, it will be heated to the pointwherethe arm B2 will move over to close a circuit through the points B".The arms B1 B2 being much better conductors than the'coil B3 and itsterminals, current suiicient to heat the coil will no longer passthrough. The arm will cool and the switch will go back to break thecircuit when the coil will again be heated depending upon the size ofthe coil and the sensitiveness ofthe switch arms. The time during whichthe circuit is closed through the points B6 may be varied at the will ofthe manufacturer. The total resistance in the light circuit through theresistance coil B3 is enough to prevent lighting of the lamp but whenthe switch points Be are closed and the resistance coil B3 is shortcircuited the current can light the lamp. The result of this is thatwhen the main switch, is closed, the lamp will flicker on a controlledrate. The resistance of the coil Ct5 is so great that when the mainswitch is closed, the grounding eect through the coil C5 and theconductor Ca is negligible.

The wire C being grounded enables a small amount of current to How atall times to maintain the resistance coil B3 in an initial- 1y heatedcondition which will cause the switch to be in constant slow operationand be in readiness to instantaneously iiash the stop light or othersignal when the main switch is closed. Moreover, the closing of the mainswitch causes the additional current taken by the stop light to owthrough the coil B3, whereupon the coil is heated more rapidly and 4themake and break points B6 are opened and closed at a much faster speedthan during the initial heating or slow operation perio It will beunderstood that the device shown in Filr'es'Q and 3 is about six timesfull size andt e unit may be placed in the wiring circuit where desiredwithout any special mounting, being supported only by the wiresthemselves.

I claim:

1. An automatic make and break switch comprising a permanently closedgenerally elongated housing, conductor wires extending into the housingthrough the opposed ends thereof, a supporting frame contained withinthe housing and supported on the ends ofsaid wires, the make and breakswitch comprising a pair of opposed bi-metall'ic heat responsive armswith contact points in opposition.

2. An automatic make and break switch comprising a permanently closedgenerally elongated housing, conductor wires extending into the housingthrou h the opposed ends thereof, a supporting rame contained within thehousing and supported on the ends of said wires, the make and breakswitch comprising a pair of opposed bi-metallic heat responsive armswith contact points in opposition, a resistancecoil wound about one ofsaid arms and in series with the two arms whereby when a circuit isclosed between the arms, the coil is short circuited.

3. An automatic make and break Switch comprising a substantially tubularhousing having closed ends, conductor wires extending intothe interiorof the housing through its ends, a pair of opposed bi-metallic heatresponsive arms having their outer ends electrically connected to andsupported by said wires, said arms having opposed contacts at their freeends, an insulated supporting base within the housing having its endsrigidly secured to the arms adjacent the outer ends thereof, wherebysaid arms are maintained in operative position, and a resistance coilwound about one of said arms, said coil having its ends connectedrespectively to said arms.

4. An automatic make and break device comprising a substantially tubularhousing having closed ends, conductor wires extending into the interiorof the housing throu h its ends, thermostatic switch elements in saldhousing in circuit with said wires, a heating coil to heat one of saidelements, said coil being connected between said elements, and a highresistance connection to the other of said elements.

5. An automatic make and break device comprising a substantially tubularhousing having closed ends, conductor wires extending into the interiorof the housing throu h its ends, thermostatic switch elements in saldhousing in circuit with said wires, a heating coil to heat one of saidelements, said coil being' connected between said elements, and a highresistance coil surrounding one of said conductors having one endconnected to the other of said elements.

6. An automatic make and break device comprising a substantially tubularhousing having closed ends, conductor wires extending into the interiorof the housing through its ends, thermostatic switch elements in saidhousing in circuit with said wires, a heating coil to heat one of saidelements, said coil being connected between said elements, and a highresistance coil surrounding one of said on said support, one ofsaidelements being responsive to temperature changes1 a heating coil toheat the temperature responsive element, said coil being connectedbetween said elements, and auxiliary connections to said coil to enablethe coil to initially heat the temperature 'responsive element) Signedat Chicago county of Cook and State of Illinois, this 23rd day ofOctober,

1929. EDWARD V. BOTTS.

